Using dead struts and lots of bearings will help. When I weigh my cars I try not too overthink all this binding stuff. and without me in the driver seat and yup, the theory is right--the cross weight
Kind of like a person standing on a bathroom scale under a low ceiling, pressing on the ceiling with his hands with some constant force. split the adjustment between all four wheels--extend the LF and RR 1 1/4 turns
. To carry the wheel load, the spring must be compressed quite a bit. For road racing and autocrossing, the ideal left weight percentage is 50 percent. That's all total speculation though. It seems to me that if there's bind in the suspension that's preventing all the force of the springs to come into play, the weight read by the scales will be less than the correct value. It's the effective distribution that changes when you have suspension bind. For our example we have LF 3.625, RF 4.75, LR 4.625, RR 5.75. McMaster-Carr adjustable end links
over). Check your tire pressure and bump it up to the hot pressure
They kept saying that it would go anywhere on the track and anywhere they pointed it. (CG) height by using this online calculator: CG Height
Corner-Weight Distribution Bickel points out that corner-weight distribution refers to the amount of weight carried by diagonally opposed pairs of wheels. MuddBoss Feature Winner at Dirt Devils RC Speedway, 12-18-2021. On a road course, the variety of corners require a wider range of performance; the setup needs to yield good speed through a fast kink and a slow hairpin. Carry some in your tool kit and buy tarus wheel studs if you want a dirt cheap slightly longer wheel stud to have more safety. I would imagine that disconnecting the shocks is only applicable to setups where the shock and spring are separate, like a lot of solid axle cars, or Mk2 Supras in my experience. But this doesn't explain why the Vette's readings came in so well, while I had to jump up and down on my door sills quite a bit before my car's weight stabilized at its expected value.
of its weight on the Left Front and Right Rear tires, and 50% on the Right Front
I commented on this to the youtubevideo on TIG welding, where they put their C5 Vette on scales and had a contest to guess the weight correctly, so I apologize for the duplicate posts. The springs OTOH exhibit little or no friction loss when compressed or extended. 2023 Motorsport Marketing. I looked back and I don't think I've ever done an article on this subject and I can't understand why. Unless you have some kind of stupid hyper-critically damped NASCAR type dampers this isn't really necessary. Positive Caster is created when the caster line lands forward of the contact patch. Let's explore some ways to do this in an orderly and sensible way. Cross Weight Calculator | Eldridge Racing | Micro, MiniSprint Parts and . It's better to make many small changes than to try
Scale Type: . the scales. Doing the multiplication to square that number, we get 1.1056. Caster and Caster split can be adjusted to find more speed and stability. This allows a slightly lower rear stance, which provides a good weight transfer entering a corner. (Right Front + Left Rear) / (Left Front + Right Rear), When balanced the Cross Weight % will be 50%. Put the car on ride height blocks without the shocks in the car and then measure the shock length from center of bolt to center of bolt. . Do not adjust any other wheel's spacing. W. William18 New member. racers only turn left we can balance the car for better grip in left
More wedge means that the car will likely understeer more in a left turn. Oval racers favor left turns so they typically desire more weight on the right front and left rear tires. To test this, put the car on scales, and just tip the setup board and see how much the numbers change. I've read all the info before, in various places, but it's good to have a refresher. To get good accuracy easily make sure you get the low hanging fruit first like removing the friction between the tires and the scales so there is no bind. The LF needs to go up 0.3125 and the RF needs to go down the same amount. Raising the rear end will also provide a little more on-power grip by keeping more weight directly above the rear tires during acceleration. The height of the rear roll center (and the front also) is critical to handling. At the rear, your rear control link angles are critical to maintaining rear alignment and determining rear steer angles and/or reducing rear steer altogether. %Right Weight =
Bite should be positive for oval racing, Wedge =
The more power a car has, the more that static weight over the drive wheels helps acceleration off the corners. rear should be the same. In the example at the beginning of the article, this was the problem: a cross-weight percentage that was less than 50 percent, and probably off by at least two percent. Ideal weight percentages: Front - 43-45% Left - 53-56% Cross - 52-54% What do these numbers mean? Bite and Wedge Delta are
Why? you run on the track. For our example we use: LF 200, RF 250 - 250 200 = 1.25 multiplier for the front. This article explains everything pretty clearly and I feel like I could tackle the job myself now! I have a 96 civic with a d16/manual. So we turn the RF adjuster up (to lower that corner) 2.5 turns and the LF down (to raise that corner) 2.5 turns. We had a good Miataset up for ST. The rear weight percentage is found in a similar manner: Add the LR and the RR weight together and divide the sum by the total weight. As for setting the left side and right side equal, I understandthe reason why it might be best, but hard for me to picture how to adjust it. 50% then Wedge Delta will be 0. few inches several times on the scales before each reading though just for good
We don't ever move weight around to get crossweight, but we do move weight to change our front-to-rear percent or the side percent of total weight. turns. (i.e., if we move the RF adjuster two rounds, then we will move the LF adjuster 2.5 rounds.) I made a 4-scale system for my off-road cars. Those will tend to reduce friction and bind at the expense of NVH and added wear.
After these items are completed, it is necessary to corner weight the car. [Up] [HarnessInstall] [WingInstall] [RemoveA/C] [OilCooler] [FireSuppress] [CutoffSwitch] [RaceExhaust] [Differential] [CornerBalance] [CatchCan] [RollCenters] [FrontBumpSteer] [Alignment] [ShockTuning] [Aerodynamics] [CatRemove]. If you have uneven mass on your wheels then your tyres will all have different levels of grip which can lead to an unpredictable car on circuit and make it corner faster in one direction than the other. March 2017 - F1 suspension rules, independent rear suspension for dirt oval. the front ramps then jack up the rear and lower it onto the rear scales. In order to perform the set up routine the car needs to be completely ready to race. One of the most important aspects of car setup is the static weight distribution and the cross-weight percentage. Before putting your car on the scales you need to power up
I don't like the lower weight ratings and plastic scale pads of proform. Plan to win in a repeatable fashion. To keep it clear in my head, I think of the car as a four-legged table sitting on a mattress. Find a fairly level spot and mark on the ground with duct tape or marker where the tires sit on the ground. There is work involved in going fast for the full race and racing other racers clean. Adjust the rear down by using the same method as in No. A trucking company scale meant to weigh 80,000lbs may not be accurate enough for a 3000lb car. 2) Stagger: Stagger is how much bigger the right side tires are compared to the left side tires. If it slows to 100rpm, the outside wheel will spin at 300rpm. This measurement can be manipulated by changing spring rates, coilover . How big is the track? lowered onto the scales the tires will need to spread out to unbind the
For most karts, the following weight distribution is recommended: 43% Front Weight 57% Rear Weight 50% / 50% Left / Right Weight These are just recommended starting points. I use this technique and it
However, most importantly you need to take care of the handling. what he means is he's adding weight to the left rear and right front
For ovals we want a
I installed
If you want to raise the ride height then extend both LF and RR coil overs
Take care that the car does not accidently slide off the scale pads. You can use rubber tires on very specific tracks and seasons. Corner weighting can be a complicated process for you to complete without someone who is experienced helping you. Motors / ESC: Any 1/10th scale motor/esc combo allowed. It will let you predict and understand the effects that various modifications have on handling, performance and lap times. Jun 7, 2018 #5 . renting/borrowing/buying some scales and corner balancing your car. More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. So 2.5" springs and experimenting is the way to go- I think I know that much.. . Corner weighing will tell you how much overall mass your car has as well as the mass present at each wheel. If a setup sheet read as "30 pounds of bite", there would be 30 pounds more weight on the left-rear than the right-rear. Wedge Delta can also be thought of
For example, if you are racing the Briggs Light class at 305 pounds, your corner weights should be: LF = 68 pounds RF = 68 pounds If you get the car neutral in left turns, it oversteers in right turns. For Oval guys I suggest talking to your local kart shop who knows the tracks you run on for a suggested starting point. If you don't have adjustable end links on your anti-roll bars
Oval racers favor left turns so they typically desire more weight
Once static weight percentages are set, work on cross-weight percentages. Always
Then move components like the battery or fuel cell. Many successful race teams use corner weighting to achieve the same F/R % on both sides equal, not cross weight. Now, look into details about the matter. A. turns. To favor right turns, put more weight on the
Since I went to 800 front and 700lb rear springs over the winter I
Classic Truck. Less tread on hard slick is good. This will pitch the vehicle's. traction or bite in left turns. box in the "Ride Height" section of each spreadsheet. Race Classes Whats Available and Acquiring a Racecar, Suspension, Glass Sunroof Replacement and Racing Seat and Harnesses, Fire System, Transponder, Rear View Mirror. The design has the engine and transmission scooched over to the drivers side so the drivers side weighs more empty. height and the shocks set to the exact same spring perch height
important for cars with upgraded (stiffer) sway bars because they can exert a
But if you corner and the inside wheel slows to 150rpm, the outside wheel will spin at 250rpm. "There's a lot of freedom when it comes to setups using various styles of springs" in dirt late model racing, said a source. Corner weighting your car is
Your car may be designed to run different ride heights than these. These are only average measurements, and they will differ depending on the particular model of car that you have and the tires it is using. They are not too suitable for racing and oval dirt cars. extra weight is on the left rear and right front tires which gives them more
I painstakingly leveled the scales and marked their locations
line above each scale and placed a ruler on the top
I needed 3 linoleum tiles (0.045" thick
However, many cars cannot make the 50 percent left-side weight percentage due to driver offset. If you do have adjustable end
A good starting point would be tank of gas. Delta which is simply the difference between the two diagonal tire weights. But stagger is not a good idea on a road course or autocross either, where the ideal is 50-percent cross-weight and no stagger. These tell us all we need to know about the setup relative to the weight distribution. Set them to hot pressures is the norm as I understand it. shouldn't match the front to the rear but your left front and right front shocks
Positive front toe (tires pointing in) generally is desirable on lightweight cars that don't have a lot of shifting weight, such as go-karts. For a car with a 17.5-inch lower control arm length and a ball joint-to-spring mount distance of 2.5 inches, you divide 17.5 by 15 (17.5-2.5) to get 1.1667 and then multiply that by itself to get 1.3611. Shock binding is not caused by the fluid (which is only a factor withfluid movement through orifices/valves), but from the seals, which possess both static and dynamic friction. stiff springs on your coil overs. Corner Weighting I run generally 34F/30R for the street and usually (again depending on the day) drop the fronts to around 30~ and the rears to 26 or 28. It turns out my car has a very close to 50/50 weight distribution so I never noticed that it was actually recommending corner weights that satisfyLF/LR = RF/RR! Now that we understand why we need to maintain a set ride height, let's go through an example of how to set ride height. supposed to. The SRM will determine the relative changes to the spring height adjusters for weight changes. how and why to corner balance a car. The angles are another way to set the suspension for the desired ride height and cross-weight percentage. It would just automatically settle. shocks set to same length left to right (front to rear will be different). The front will show close to 60%. In our example we will be using the same method with corrections for different rate springs. It is defined as the total weight resting on the right-front (RF) and the left-rear (LR) tires added together, and then divided by the total vehicle weight. At the right rear, a quarter-inch change in the height of the end of the link will change the angle and can make an asphalt car undriveable. Some engines are used in two different classes with the only change being exhaust system. I highly recommend using a laser level to confirm the 4 scales are level to one
For pure race cars this isnt a consideration. Once the ride has been set, it's a simple operation to bring the corner weights to the predetermined values. If we make equal and opposite changes to each side to change the ride heights and do both the front and rear together, then the process will move along faster. To calculate cross-weight percentage, add the RF weight to the LR weight and divide the sum by the total weight of the car. 2. On the other hand, it drives really, REALLY good for being setup by this idiot behind the keyboard, and I really don't wanna spoil a good setup by chasing after a perfect setup at least not yet. My track width with CE28 17" x 9" wheels
Wheelbase: 9.5" min, 11.5" max Maximum width: 10.250" Minimum weight: 57.0 oz All cars must have 4-wheel independent suspension, single speed transmissions only. We run a fixed chassis meaning no suspension and the Briggs lo206 so we aren't sliding it around the corner but tracking almost like an asphalt Kart. TVW CWP FWP or, 2,800 0.52 0.51 = 685B. Are they adjustable? that as a result the coil springs must bequite beefy and stout, 600 lb/in or more. So LF/LR = RF/RR is what you shoot for. If you align your car prior to doing the corner weights, it will be necessary to verify the alignment again after the corner weighting is completed. Disconnect and adjust later. Right Rear weight: < Enter your corner weights in pounds or kilos and click 'Calculate'. track are left turns then having more weight on the Right Front and Left Rear
I
Get the numbers right and the percentages will follow. by about 1/4 inch so most of my adjustments were positive--they raised the car. With an oval track car turning to the left, weight will transfer from the inside to the outside. Since oval
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I plugged in a bunch of numbers into my calculator and it all checks out. If you want to raise the front of the car then extend only the
The tiles & salt seemed to help because the weight never
On oval track cars, cross-weight is usually used in conjunction with stagger (where the right rear tire is larger in circumference than the left rear tire) to balance handling. Andy Hollis does this. Wedge Delta should be positive for oval racing. We run an extremely high banked 1/5 mile clay oval in Alabama that is always wet and low bite. 9. about 1/8" of wheel movement) to reduce the weight on the right front and left
Road racers are
turn and ended up with a perfect 50.0% cross weight. close to where I wanted it. You can also use this online calculator to compute your corner
as Left Rear Bite + Right Front Bite. Lay the bag flat onto the scale pad, partially open to vent, lower the car into the bag. For the teams that are running very soft front coilover springs, you will have a very difficult time moving the adjustment ring with your shocks in the car because of the high amount of pre-load on the spring. Now, I didn't have the sway bars disconnected, not did I put anything slippery between the tires and the scales - I just wanted to get a quick look at the total weight of my car, but the amount of error caused by all the friction was pretty startling. two years. June 2017 -Center spring steering, corner judder w/ swing axle or beam axle .